Twist drill gauge



3 Ap 8, 1952 E. BLISS 2,592,003

TWIST DRILL GAUGE Filed Aug. 13, 1946 W INVEJQTOR.

Patented Apr. 8, 1952 g y 2,592,003 UNITED STATES PATENT OFFICE TWIST DRILL GAUGE Emmitt Bliss, Fort Wayne, Ind.

Application August 13, 1946, Serial No. 690,173

7 Claims. 1

This invention relates to improvements in a twist drill gauge by which toascertain the relative slant of its cutting edges.

An object of the invention is to afford a device by which is readily detected inaccuracy in the grinding of twist drills of Various sizes.

And another object of the invention is to provide means of adjustment for gauge members applicable to drill points to determine with precision the relative angularity of the cutting edges thereof.

Other objects and advantages of the invention appear in the following description.

An illustrative embodiment of the invention is shown in the accompanying drawings, in which:

Fig. 1 is a top plan view of a structure in which the invention is incorporated; and

Fig. 2 is a vertical central section of Fig. l.

The illustrative embodiment of the invention consists of a housing 3 having a light chamber 4 therein. The top wall 5 of the housing preferably is inclined and has an opening 6 through which light is emitted from a lamp 1 that is disposed within the light chamber. The vertical walls 89-l ll-I l of the housing project slightly beyond the wall 5 so as to form an open cavity l2 in the top of the housing, encompassed by the projecting upper ends of the vertical walls, in which is disposed a guide-plate l3 that is held in position against the wall 9 by means of cleats l4 positioned between the wall 8 and adjacent face of the guide-plate. In the guide-plate is an elongated sight opening E5 the opposite end portions of which diverge forwardly from its midportion and overlie the opening 6 in the wall 5 of the housing.

On the guide-plate l3 are removably positioned gauge-blocks l6 and H, the rear ends of which rest against a rail I8 that projects upwardly along the rear margin of the gauge-plate which forms an abutment therefor.

The outer end of the gauge-block l6 abuts the inner face of the end wall of the housing, and the other gauge-block I! has lateral sliding movement between the rail l8 and the corresponding cleat, movement being imparted to the sliding gauge-block by means of an adjusting rod l9 that is threaded in a lug 20 on the end Wall ID of the housing. The adjusting rod has on its outer end an operating thumb-piece 2| and on its inner end a stem provided with a head 22 that is disposed in a T-shaped socket 23 made in the gauge block I1, the arrangement being such that upon turning of the adjusting rod the gauge-block I! is moved laterally in one direction or-the other accordingly as the adjusting rod is turned. In the gauge-blocks l6 and l! are made guide-slots 24 and 25 respectively in which are disposed corresponding sliding bars 26 and 21 that are held in adjusted positions therein by means of individual clamps 28-49 provided with corresponding thumb-nuts 28'29. The clamps are secured to the gauge-plates and overlie the corresponding sliding bars which thereby are held in selected adiusted positions when the thumb-nuts are tightened.

The sliding bars are equangularly disposed with respect to each other, and their innermost ends are mitred so that when oneof the bars is positioned across the path of the other bar,and contact is made therebetween, the mitred end of the one bar-fits snugly against the adjacent side of the other, thus obstructing light emitted through the openings in the top wall of the housing and guide-plate where the bars contact.

Operation In use, a drill to begauged is inserted between the gauge-blocks arid clamped therebetween by manipulation of the adjusting rod and with the point of the drill disposed over the sight opening I5 and its cutting edges extending laterally. The sliding bars are then adjusted so the mitred end of one bar 26 abuts the adjacent side of the other bar 21 and the point of the drill is located precisely in the vertex of the angle formed by the near sides of the bars. Upon' 'energization of the lamp, the light emitted therefrom through the openings-in the housing and guide-plate is completely obstructed in the event the cutting edges of the drill contact uniformly with the corresponding sliding bars, thus indicating that the cutting edges of the drill have equal angularity. However, if the opposite cutting edges of the drill point are of unequal angularity, such discrepancy, and the extent thereof, is readily observable by the operator because of variations in the amount of light emitted between the cutting edges of the drill and the corresponding adjacent sides of the sliding bars. Thus, the operator is enabled to determine where further dressing of the cutting edges of the drill is required for correction of the angularity thereof. Y 7

By use of the gauge thus constructed the degree of accuracy with which the drill has been ground, or any inaccuracy and the location thereof are readily ascertained simply by observation of the light, if any, emitted between the cutting edges of the drill and the divergent bars.

Variations from the particular construction above disclosed maybe resorted to by the exercise of skill in the art, without departure from the spirit or scope of the invention. p

What I claim is:

1. A gauge for twist drills by which to determine the relative angularity of their cutting edges, said gauge consisting of a housing having a light chamber containing a lamp and provided with an opening, a guide-plate seated on the housing having an upwardly extending rail and provided with a sight opening therein alined with the, other opening, the opposite end portions of said sight opening having angular divergence, cleats securing said guideplat'e"in position on the housing, a gauge-block on said guide-plate secured between one of said cleats and the rail, another laterally movable gauge-block located between the other cleat and the rail and provided with adjusting means therefor, sliding bars disposed in corresponding grooves in said gaugeblocks equangularly disposed with respect to each other, the inner ends of said bars being mitr ed so that when one of the bars is positioned so as to overlap the other bar and contact is made therebetween, the mitred end of the one bar fits snugly against the adjacent side of the'other bar, thus to obstruct light emitted from the lamp through the openings in the housing and guidepIate'Wherethe overlapping bars contact, and clamps on said gauge-blocks to secure said bars in adjusted positions.

2."Afgauge for twist drills by which to determine "the relative angularity of their cutting edgesgsaid gauge consisting of a housing having a light chambercontaining a lamp and provided with an opening, a"-guide-'plate seated on the housing having an upwardly extending rail and provided with a sight opening therein alined with the other opening, the opposite end portions of said sightopening having angular divergence, a gauge-block secured on said guideplate, another laterally movable gauge-block provided withadjustingmeans therefor, sliding bars disposed in corresponding grooves in said gauge-blocks equangularly disposed with respect to each other; the inner ends of said bars being mitred'so that when one of the bars is positioned so as to overlap the other bar and contact ismade therebetween, the mitred end of the one bar fits snugly against the adjacent side of the other bar, thus to obstruct light emitted from the lamp through the openings in; the housing and guideplate where the overlapping bars contact, and clamps'on said gauge-blocks to secure said bars inadjusted positions.

3. A gauge for the. cutting edges of drills consisting-of a chambered housing provided with aSlzmp-therein' and having; an opening, a guideplate on. saidhousing having a sight opening alined-with the other opening, the ends thereof being divergent, opposite. gauge-blocks on the guide-plate overlying the. sight opening, adjusting means to; move one of said gauge-blocks toward-"or from the other gauge-block, divergent slidingbars having guided movement respectively on said gau'ge-blocka-the inner ends of which overlap corresponding portions of'the sight opening when the end of one bar contacts the adjacent'side of theother bar, and clamps for securing said bars in'adjusted positions.

4. A gauge forthe; cutting edges of drills consisting. of a chambered housing provided with a lamp therein and having an opening, augeblocks on the housing disposed oppositely in juxtaposition with said opening, adjusting means in connection with-one of said gauge-blocks for movementthereof toward or from the other guide-block to provide a variable gap therebetween for a drill, divergent bars having guided sliding movement on said gauge-blocks, the inner ends of which overlap portions of said opening, the'arrangement'bein'g "such that when a drill ispositioned in the gap with the cutting edges thereof in contactwith' said bars, light emitted from the lamp throughthe opening is discernable between the cuttingedgesfof the drill and the barscontacted thereby'if the -angularity of said euttin'gedgesand the bars difier, thus indicating inaccuracyingrinding bfthe drill.

5. A gauge for drills to determine the relative angularity of the cutting edges thereof, said gauge consisting of a housing having a light chamber containing a lamp and an opening for the emission of light therethrough from the lamp, a guide-plate disposed on the housing provided with a sight opening therein located over the opening in the housing, two gauge-blocks positioned on the guide-plate having relative movement toward and from each other provided with adjusting means therefor, the opposing sides of said gauge-blocks overlapping the corresponding sides of the sight opening, and divergent bars having sliding movement on said gauge-blocks respectively provided with means for securing same in adjusted positions respecting said gauge blocks, the end of one bar being adapted to contact with the adjacent side of the other so as to obstruct passage of light emitted from the lamp through said openings.

6. A gauge for drills to determine the relative angularity of the cutting edges thereof, said gauge consisting of a housing having a light chamber containing a lamp and an opening for the emission of light therethrough from the lamp, two gauge-blocks mounted on the housing in a common plane for relative movement toward and from each other provided with ad justing means therefor, the opposing sides of said gauge-blocks overlapping said opening, and divergent bars havin sliding movement on said gauge-blocks respectively provided with means for securing same in adjusted positions respecting said gauge-blocks, the end of one bar being adapted to contact with the adjacent side of the other so as to obstruct passage of light emitted from the lamp through said opening.

7. A gauge for drills to determine the relative angularity of the cuttin edges therefor consisting of two gauge-blocks the bottom surfaces of which arecoplanar, mounted for relative movement toward and from each other and provided with adjusting means therefor, divergent bars having sliding movement on said gauge-blocks respectively, the inner ends of said bars being mitred at definite angles so that when one bar overlaps the end of the other bar, the side thereof is in contact with the mitred end of said other bar thus obstructing light from passage therebetween, and means for securin said bars in adjusted position.

EMMITT BLISS.

REFERENCES CITED- The following references are of record in the file of this patent:

UNITED STATES PATENTS.

Number Name Date 303,368 Goldthwait Aug. 12, 1884 1,622,776 Fisher Mar, 29,- 1927 1,630,299 Johnson May 31, 1927 2,146,599 Smith Feb} '1, 1939 2,413,198 Stewart Dec. 24,1946

FOREIGN PATENTS Number Country Date 272,589 Italy Mar. 14, 1930 559,624 Great Britain Feb. 28, 1944 591,769 Great Britain Aug. 28, 1947 OTHER REFERENCES A Gage for Drill-Points," Falck, June "7, 1933,- American Machinist, pages 381 to 382. 

